BACKGROUND

[0001] Electroplating can be used in integrated circuit manufacturing processes to deposit electrically conductive films onto substrates. Electroplating involves the electrochemical reduction of dissolved ions of a selected metal to an elemental state on the substrate surface, thereby forming a film of the selected metal on the substrate. Electroplating of multiple ion species may be used to generate a solder precursor which may be converted into an alloy upon application of heat.

SUMMARY

[0002] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

[0003] Examples are disclosed that relate to adding a plating component to an anode chamber flow loop of an electroplating apparatus. In one example, an electroplating apparatus comprises one or more anode chamber flow loops, each anode chamber flow loop comprising an anode chamber configured to contain an anolyte solution and an anode. The electroplating apparatus further comprises a flow meter configured to dose components of the anolyte solution into each anode chamber flow loop. The electroplating apparatus further comprises a first valve manifold configured to supply components of the anolyte solution to the flow meter. The first valve manifold comprises a first shutoff valve operable to selectively fluidly couple a source of water to the flow meter, and further comprises a second shutoff valve selectively operable to fluidly couple sources of acid and bulk inorganic plating components to the flow meter. The electroplating apparatus further comprises a second valve manifold fluidly coupled to the second shutoff valve. The second valve manifold comprises a third shutoff valve selectively operable to fluidly couple the source of inorganic plating components to the first valve manifold, and further comprises a fourth shutoff valve selectively operable to fluidly couple the source of acid to the first valve manifold. [0004] In some such examples, the electroplating apparatus additionally or alternatively comprises a check valve positioned between the fourth shutoff valve and the source of acid.

[0005] In some such examples, the third shutoff valve is additionally or alternatively a normally-closed valve.

[0006] In some such examples, the fourth shutoff valve is additionally or alternatively a normally-open valve.

[0007] In some such examples each anode chamber flow loop is additionally or alternatively a recirculating closed loop system comprising a pump configured to circulate anolyte through the anode chamber.

[0008] In some such examples each anode chamber flow loop additionally or alternatively comprises one or more tower reservoirs.

[0009] In some such examples, the source of acid additionally or alternatively comprises methanesulfonic acid.

[0010] In some such examples, the third shutoff valve is additionally or alternatively configured to, when closed, allow the source of bulk inorganic plating components to be fluidly coupled to a reservoir.

[0011] In some such examples, the bulk inorganic plating components additionally or alternatively comprise the dissolved metal species, and wherein the dissolved metal species precipitates in water.

[0012] In some such examples, the dissolved metal species additionally or alternatively comprises tin.

[0013] In another example, a method is disclosed for operating an electroplating apparatus. The method comprises, during a startup phase, flushing an anode chamber flow loop with an acid pumped via an anolyte component supply system comprising at least a first valve manifold. During the startup phase, the method further comprises supplying the anode chamber flow loop with a tin solution from a supply fluidly coupled to the first valve manifold, and flushing the anolyte component supply system with the acid. During an electroplating phase, the method comprises selectively dosing the anode chamber flow loop with acid and water via the first valve manifold responsive to signals received from one or more sensors of the anode chamber flow loop, and restricting flow of the tin solution to the first valve manifold.

[0014] In some such examples, water is additionally or alternatively directed through the first valve manifold via a first shutoff valve, and wherein acid and the tin solution are additionally or alternatively selectively directed through the first valve manifold via a second shutoff valve.

[0015] In some such examples, the tin solution is additionally or alternatively selectively directed to the first valve manifold via a third shutoff valve comprised in a second valve manifold, upstream of the first valve manifold, and wherein acid is additionally or alternatively selectively directed to the first valve manifold via a fourth shutoff valve in the second valve manifold.

[0016] In some such examples, restricting flow of the tin solution to the first valve manifold additionally or alternatively comprises restricting opening of the third shutoff valve.

[0017] In some such examples, the method additionally or alternatively comprises, during a maintenance phase following the electroplating phase, draining the anode chamber flow loop, removing restrictions on opening the third shutoff valve, and flowing the tin solution to the first valve manifold by opening the third shutoff valve. [0018] In some such examples, supplying the anode chamber flow loop with the tin solution additionally or alternatively comprises ceasing to supply the anode chamber flow loop with the tin solution responsive to a signal received from a level sensor comprised in a tower reservoir of the anode chamber flow loop.

[0019] In another example, an electroplating apparatus comprises one or more anode chamber flow loops, a flow meter configured to dose components of the anolyte solution into each anode chamber flow loop, and a first valve manifold configured to supply the components of the anolyte solution to the flow meter. The first valve manifold comprises a first shutoff valve operable to selectively fluidly couple a source of water to the flow meter, and a second shutoff valve selectively operable to fluidly couple a source of methanesulfonic acid and tin solution to the flow meter. The electroplating apparatus further comprises a second valve manifold fluidly coupled to second shutoff valve. The second valve manifold comprises a third shutoff valve selectively operable to fluidly couple the source of tin solution to the first valve manifold. The second valve manifold also comprises a fourth shutoff valve selectively operable to fluidly couple the source of acid to the first valve manifold. The electroplating apparatus also comprises a controller configured to control the electroplating apparatus to supply each anode chamber flow loop with the tin solution during a startup phase. The controller is further configured to control the electroplating apparatus to selectively dose each anode chamber flow loop with acid and water via the first valve manifold by selectively opening and closing the first shutoff valve and the second shutoff valve while restricting supply of tin solution during an electroplating phase.

[0020] In some such examples, the controller is configured to restrict supply of tin solution during the electroplating phase by preventing opening of the third shutoff valve via a pneumatic force

[0021] In some such examples, the controller is configured to restrict opening of the third shutoff valve additionally or alternatively by presenting a safety warning to an operator via a user interface.

[0022] In some such examples, the controller is additionally or alternatively configured to, during a maintenance phase following the electroplating phase, drain each anode chamber flow loop, remove restrictions on opening the third shutoff valve, and flow the tin solution to the first valve manifold by opening the third shutoff valve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a block diagram of an example electroplating tool.

[0024] FIG. 2 schematically shows an example electroplating apparatus comprising an anode chamber flow loop.

[0025] FIG. 3 schematically shows an example electroplating apparatus configured for dosing metal solution into an anode chamber flow loop.

[0026] FIG. 4 shows a flow diagram depicting an example method for operating an electroplating apparatus.

[0027] FIGS. 5-9 schematically show the electroplating apparatus of FIG. 3 in various states of operation.

[0028] FIG. 10 shows a block diagram of an example computing system.

DETAILED DESCRIPTION

[0029] The term “anode” may generally represent an electrode material that is electrochemically oxidized during an electroplating process.

[0030] The term “anode chamber” may generally represent a physical structure configured to hold at least an anode and anolyte in a way that provides selective separation from a cathode chamber.

[0031] The term “anode chamber flow loop” may generally represent a system for circulating anolyte through the anode chamber. [0032] The terms “anolyte” and “anolyte solution” may generally represent a liquid environment, in which an anode is located during electroplating.

[0033] The term “anolyte component supply system” may generally represent a physical system configured to add individual components of an anolyte to an anolyte solution.

[0034] The term “bulk inorganic plating component” may generally represent a solution containing one or more inorganic species utilized for deposition during electroplating.

[0035] The term “cathode” may generally represent a conductive layer on a substrate that is grown during electroplating by the electrochemical reduction of ions.

[0036] The term “catholyte” may generally represent a liquid environment in which a cathode is located during electrodeposition.

[0037] The term “check valve” may generally represent a valve that allows flow of a fluid in one direction, and restricts flow of fluid in an opposite direction.

[0038] The terms “electrodeposition”, “electroplating”, and variants thereof may generally represent a process in which dissolved ions of an element are reduced on a substrate surface to deposit a film of the element.

[0039] The term “dosing” may generally represent a metered addition of a volume or molar quantity of one or more liquid components into a multi-component solution.

[0040] The terms “electroplating tool” and “electroplating apparatus” may generally represent a machine configured to perform electroplating.

[0041] The term “flow meter” may generally represent a device configured to measure and selectively control the flow rate of a liquid therethrough.

[0042] The term “high-resistance virtual anode” (HRVA) may generally represent a structure positioned between a substrate holder and an anode of an electroplating tool through which ions flow from the anode to the cathode during electroplating.

[0043] The term “plating cell” may generally represent a station in an electroplating tool configured for processing a substrate.

[0044] The term “reservoir” may generally represent compartments of solutions used in electroplating, such as catholyte and anolyte solutions. A “tower reservoir” is a type of reservoir. [0045] The term “shutoff valve” may generally represent a valve that can be selectively adjusted to allow or disallow flow of a fluid therethrough.

[0046] The term “substrate” may generally refer to a structure on which a film may be deposited via electroplating. Example substrates include semiconductor wafers. [0047] The term “substrate holder” may generally represent a structure for holding a substrate during an electroplating process.

[0048] The term “valve manifold” may generally represent a structure or device that houses one or more valves for controlling the flow of fluid through a system.

[0049] A variety of metals and metal alloys can be deposited by electroplating. Examples include copper, tin, silver, tin-silver alloys, nickel, gold, indium, and cobalt. One example use for electroplating is to form films for solder pads. For example, Sn/Ag alloys are less hazardous than solders containing lead, and can be deposited by electroplating.

[0050] Alkanesulfonic acids, such as methanesulfonic acid (MSA), may be used in electroplating systems due to their ability to solubilize metals such as tin, lead, silver, copper, and zinc. When an MSA solution containing metal ions is brought into contact with a substrate seed layer during an electroplating process, the metal ions are electrochemically reduced at the surface to form a metal layer.

[0051] Tin, while soluble in MSA, may precipitate from an electroplating solution in some aqueous conditions. As acid and water are typically dosed into anolyte during electroplating procedures, dosing may be performed in a manner that keeps tin out of supply lines. Otherwise, residual tin may form deposits in the lines when water is dosed. As such, tin-MSA solutions may have to be manually supplied into anolyte reservoirs. This may pose both a health hazard and a potential point of error in a process that may be concentration dependent.

[0052] Accordingly, examples are disclosed that relate to adding components of an anolyte solution to an anolyte chamber flow loop in an electroplating apparatus. Via the examples described herein, sources of acid, water, and bulk inorganic plating components, such as a tin solution, can each be supplied directly to the anode chamber flow loop. This allows for the introduction of tin solution with reduced risk of exposing personnel operating the electroplating apparatus.

[0053] Prior to discussing these examples in more detail, FIG. 1 schematically shows a block diagram of an example electroplating tool 100. Electroplating tool 100 comprises a plating cell 102 including an anode chamber 104 and a cathode chamber 106. Electroplating tool 100 further comprises a selective transport barrier 108 and a HRVA 109 separating the anode chamber 104 and the cathode chamber 106. Anode chamber 104 comprises an anode 110. Anode chamber 104 further comprises an anolyte in contact with anode 110. Cathode chamber 106 comprises a catholyte. The catholyte comprises an ionic species to be deposited on a cathode layer of a substrate

111 as a metal by electrochemical reduction. Anode 110 comprises the metal being deposited. Electrochemical oxidation of anode 110 at least partially replenishes the ionic species consumed by the electroplating process. A bulk inorganic plating component solution also is added at times to replenish the ionic species.

[0054] Selective transport barrier 108 allows a separate chemical and/or physical environment to be maintained within anode chamber 104 and cathode chamber 106. For example, selective transport barrier 108 may be in the form of a membrane configured to prevent non-ionic organic species from crossing the barrier while allowing metal ions to cross the barrier. HRVA 109 comprises an ionically resistive element that approximates a suitably constant and uniform current source in proximity to a substrate cathode.

[0055] Substrate holder 112 is coupled to a substrate holder movement system 113 including a lift 114 that is configured to adjust a spacing between substrate holder

112 and HRVA 109. For example, lift 114 may lower substrate holder 112 to position substrate 111 within the catholyte for electroplating. Lift 114 further may raise substrate holder 112 from the catholyte after electroplating. Substrate holder movement system 113 further may include components to control the opening and closing of substrate holder 112.

[0056] The catholyte may be circulated between cathode chamber 106 and a catholyte reservoir 120 via a combination of gravity and one or more pumps 122. Likewise, the anolyte may be stored in and replenished from an anolyte reservoir 124. Anolyte may be circulated through anolyte reservoir 124 and anode chamber 104 via a combination of gravity and one or more pumps 126.

[0057] In some electroplating tools, plating operations maybe performed in parallel on multiple substrates using multiple plating cells. In some such examples, central catholyte and/or anolyte reservoirs may supply multiple plating cells with catholyte and/or anolyte. In other such examples, separate catholyte and/or anolyte reservoirs may be used to supply multiple plating cells. In yet other examples, an electroplating tool may comprise a single plating cell. Where an electroplating tool comprises multiple plating cells, a single lift may be configured to lift two or more substrate holders for two or more different plating cells.

[0058] Substrate holder 112 is lowered by lift 114 toward HRVA 109 after substrate I l l is loaded into substrate holder 112. Substrate 111 faces a surface of the HRVA 109, and is spaced from HRVA 109 by a plating gap during electroplating, as mentioned above. An electric field is established between anode 110 and substrate 111. This field drives dissolved metal cations from anode chamber 104 into cathode chamber 106. At the substrate 111, the metal cations are electrochemically reduced to deposit on the cathode layer on substrate 111. An anodic potential is applied to anode 110 via charge plate 115 and a cathodic potential is provided to the cathode of substrate 111 via a cathode electrical connection 116 to form a circuit. In some examples, substrate holder 112 may be rotated via a rotational motor 117 during electroplating.

[0059] Electroplating tool 100 further comprises a computing system 130, aspects of which are described in more detail below with regard to FIG. 10. Computing system 130 may include instructions executable to control any suitable functions of electroplating tool 100, such as electroplating processes, substrate loading/unloading processes, and anolyte dosing processes, etc. In some examples, computing system 130 may be configured to communicate with a remote computing system 140 via a suitable computer network. Remote computing system 140 may comprise any suitable computing system, such as a networked workstation computer, an enterprise computing system, and/or a cloud computing system, as examples. It will be understood that remote computing system 140 may be in communication with and control a plurality of electroplating tools in some examples.

[0060] Anolyte reservoir 124 and anode chamber 104 may be components of an anode chamber flow loop, whereby pump 126 circulates anolyte in a closed-loop circuit. Components of the anolyte can be replenished during electroplating as metal is deposited and other components are consumed.

[0061] FIG. 2 schematically shows an example anolyte supply system 200 for an electroplating apparatus. Anolyte supply system 200 includes one or more anode chamber flow loops. A first anode chamber flow loop 205 is shown in some detail. A second anode chamber flow loop 207 is shown more generally. Additional anode chamber flow loops may be included in some examples. Each anode chamber flow loop includes at least one anode chamber. Each anode chamber is configured to contain an anolyte solution and an anode comprising a metal to be deposited on the cathode. A single filter 210 is shown upstream of first anode chamber flow loop 205. In some examples, each anode chamber flow loop may receive anolyte components through a dedicated upstream filter. In other examples, a single filter may be positioned upstream of all anode chamber flow loops.

[0062] As shown, first anode chamber flow loop 205 comprises a recirculating closed loop system that includes a filter 210, a circulating pump 212, a first anode chamber 214, a second anode chamber 216, and a tower reservoir 218. First anode chamber 214 and second anode chamber 216 are examples of anode chamber 104. While first anode chamber 214 and second anode chamber 216 are shown in parallel within first anode chamber flow loop 205, in some examples the anode chambers may be configured in series. Circulating pump 212 is an example of pump 126. Tower reservoir 218 is an example of anolyte reservoir 124.

[0063] Tower reservoir 218 may act as a surge volume for first anode chamber flow loop 205, and in particular for one or both first anode chamber 214 and second anode chamber 216, ensuring that the anode chambers and their respective plating cells are replenished with anolyte during operations. Level sensors 220 (high) and 222 (low) may provide an indication of the amount of anolyte in tower reservoir 218 to controller 225 via one or more sensor interfaces 227. As described further herein, controller 225 may utilize signals from level sensors 220 and 222 to adjust operations of anolyte supply system 200. For example, controller 225 may utilize such signals to conduct electroplating operations when tower reservoir 218 is sufficiently full. Controller 225 further may be configured to suspend electroplating operations when the level of anolyte in tower reservoir decreases below a threshold. In other examples, each anode chamber may be fluidly coupled to a corresponding dedicated tower reservoir.

[0064] First anode chamber flow loop 205 and second anode chamber flow loop 207 are coupled to an anolyte component supply system 230 via loop isolation valves 232 and 234, respectively. Anolyte component supply system 230 may be operable to provide bulk (e.g., flushing) and/or metered (e.g., dosing) flow of one or more anolyte components to first anode chamber flow loop 205 and second anode chamber flow loop 207.

[0065] As shown, anolyte component supply system 230 may selectively flow a source of water 235 (e.g., deionized water) and a source of acid 237 (e.g., acid in aqueous solution) to anode chamber flow loops 205 and 207. As shown, source of water 235 and source of acid 237 may be fluidly coupled to a first valve manifold 240. First valve manifold 240 includes a first shutoff valve 242 and a second shutoff valve 244. First shutoff valve 242 may be selectively operable to fluidly couple a source of water to flow meter 246. Second shutoff valve 244 may be selectively operable to fluidly couple source of acid 237 to flow meter 246. In some of the examples described herein, first shutoff valve 242 and second shutoff valve 244 are opened alternately. For example, first shutoff valve 242 may be normally open while second shutoff valve 244 may be normally closed. The two valves may be operatively connected such that opening one valve closes the other.

[0066] Flow meter 246 may be configured to dose components of the anolyte solution into anode chamber flow loops 205 and 207 via anode supply valve manifold 250. Anode supply valve manifold 250 includes a high flow shutoff valve 252, and a low flow shutoff valve 254 positioned in series with flow restrictor 256. The outputs of high flow shutoff valve 252 and low flow shutoff valve 254 are directed to directional valve 258. Directional valve 258 may be operable to selectively couple the dosing flow meter 246 to either anode chamber flow loops 205 and/or 207 or with drain line 260. Coupling flow meter 246 to drain line 260 may be used to aspirate the contents of flow loops 205 and/or 207, while coupling flow meter 246 to flow loops 205 and/or 207 allows for the dosing of components of the anolyte solution (e.g., water, acid) during electroplating operations. For example, a calibration period may occur at the beginning of an electroplating operation, then directional valve 258 may be switched to direct solutions to the flow loops.

[0067] High flow shutoff valve 252 may be used to fill flow loops 205 and 207 with components of the anolyte solution relatively quickly, such as during maintenance or resetting between operations. Low flow shutoff valve 254 may be used to provide highly regulated amounts of anolyte solution components through flow restrictor 256.

[0068] A separate bulk chemistry circuit 270 is shown that includes a bulk chemistry supply comprising tin solution source 272 coupled to reservoir 274 via reservoir fill valve 276. Reservoir 274 may be an example of catholyte reservoir 120. In the example shown in FIG. 2, bulk chemistry circuit 270 is an isolated system. Tin solution source 272 may be a pressurized line provided at the customer level, and may contain a concentrated solution that comprises tin ions for plating. For example, tin solution 272 may be supplied at 100-400 grams per liter in an aqueous solution that contains MSA. In other examples, a bulk plating component source other than a tin solution source may be used. [0069] For some electroplating chemistries, electroplating components and/or other anolyte components may be provided into anolyte component supply system 230 directly or via reservoir 274. For example, copper, in the form of aqueous copper sulfate in acidic solution, can be directly fed from a bulk supply line into tower reservoir 218 via first valve manifold 240. Copper solution may be supplied via an additional inlet to second shutoff valve 244, or via an additional dedicated shutoff valve.

[0070] However, for tin (e.g. tin-silver) electroplating, such an arrangement is not feasible, as tin precipitates out of solution in the presence of water, forming deposits which may clog the valves and supply lines of anolyte supply system 200. Tin solution 272, if supplied from a bulk chemistry supply, is only directed to reservoir 274. To supply tin solution 272 into tower reservoir 218, anolyte supply system 200 is generally primed with MSA, and then tin solution is poured manually into the top of tower reservoir 218.

[0071] Manual pouring tin can pose a risk to personnel and property in the case of spillage and chemical vapors, as tin solution can be an irritant. As such, handling tin requires the use of additional Personal Protective Equipment (PPE). One potential method for avoiding manually adding tin to tower reservoir 218 is temporarily swapping out acid component 237 for tin. However, changing chemistry in this way requires lengthy flushing of the supply lines, and changing the bottle configuration can be both a significant labor task and a safety concern.

[0072] Another potential solution is to rely on the tin anode to supply all tin for the electroplating process, and not add tin to tower reservoir 218. Supplying MSA to the anolyte chamber will dissolve the tin anode to create metal ions for plating. Some of the plated tin is replenished through breakdown of the anode, while the plated tin is replenished via addition to the catholyte. However, the MSA breakdown of tin metal takes time, and the system can be controlled more accurately if it is pre-loaded with tin solution. As such, it is desirable to be able to dose tin solution into anode chamber flow loop 205.

[0073] Accordingly, FIG. 3 schematically shows an example anolyte supply system 300 for an electroplating apparatus to accommodate dosing of tin solution. Anolyte supply system 300 includes first and second anode chamber flow loops 305 and 307, and a filter 310. As shown, first anode chamber flow loop 305 comprises a recirculating closed loop system that includes a circulating pump 312, a first anode chamber 314, a second anode chamber 316, and a tower reservoir 318. Level sensors 320 (high) and 322 (low) may provide an indication of the amount of anolyte in tower reservoir 318 to controller 325 via one or more sensor interfaces 327. Although first anode chamber 314 and second anode chamber 316 are shown in parallel within first anode chamber flow loop 305, in some examples the anode chambers may be configured in series.

[0074] First anode chamber flow loop 305 and second anode chamber flow loop 307 are coupled to an anolyte component supply system 330 via loop isolation valves 332 and 334, respectively. As shown, anolyte component supply system 330 may selectively flow a source of water 335, and a source of acid 337 (e.g., acid in aqueous solution) to anode chamber flow loops 305 and 307. As shown, source of water 335 is fluidly coupled to first valve manifold 340. First valve manifold 340 includes a first shutoff valve 342 and a second shutoff valve 344. First shutoff valve 342 may be selectively operable to fluidly couple a source of water to flow meter 346. Second shutoff valve 344 may be selectively operable to fluidly couple source of acid 337 or tin solution 372 to flow meter 346 via second valve manifold 382.

[0075] Flow meter 346 may be configured to dose components of the anolyte solution into anode chamber flow loops 305 and 307 via anode supply valve manifold 350. Anode supply valve manifold 350 includes a high flow shutoff valve 352, and a low flow shutoff valve 354 positioned in series with flow restrictor 356. The outputs of high flow shutoff valve 352 and low flow shutoff valve 354 are directed to directional valve 358. Directional valve 358 may be operable to selectively couple anode chamber flow loops 305 and 307 with either flow meter 346 or with drain line 360. A bulk chemistry circuit 370 is shown that includes tin solution supply 372 coupled to reservoir 374 (e.g., catholyte reservoir) via reservoir fill valve 376.

[0076] Bulk chemistry circuit 370 further comprises a direct pathway from supply of tin solution 372 into anolyte component supply system 330 and thus into anode chamber flow loops 305 and 307. In this example, a supply line 380 directs tin solution from the source of tin solution 372 into first manifold 340 at second shutoff valve 344 via second valve manifold 382. Supply line 380 thus receives tin solution directly from the pressurized source 372. Second valve manifold 382 also receives acid solution from MSA source 337. Second valve manifold 382 comprises a single output that feeds into second shutoff valve 344, selectively fluidly coupling source of acid 337 to first valve manifold 340. MSA may be supplied at any suitable concentration, such as 70%. This configuration allows for automatic or semi-automatic filling of anode chamber flow loops 305 and 307 with tin solution during a startup phase, as described in more detail below.

[0077] A third shutoff valve 384 selectively fluidly couples tin solution 372 to second shutoff valve 344. A fourth shutoff valve 386 selectively fluidly couples MSA source 337 to second shutoff valve 344. In some examples, third shutoff valve 384 may be a normally-closed valve, while fourth shutoff valve 386 may be a normally-open valve. In this way, tin solution 372 is restricted from entering anolyte component supply system unless directly commanded to do so by controller 325. To prevent against backflow of pressurized tin solution in the event of a failure of fourth shutoff valve 386, a check valve 388 may be positioned in the MSA flow path upstream of fourth shutoff valve 386. Controller 325 may control third shutoff valve 384 and fourth shutoff valve 386 via pneumatics bank 390. For example, third shutoff valve 384 and fourth shutoff valve 386 may be slaved together such that opening one valve closes the other.

[0078] In the configuration of FIG. 3, tin solution can be dosed without being manually poured into tower reservoir 318. This avoids exposure of users to tin solution when dosing tin solution, and also may reduce labor requirements. Further, anolyte supply system 300 helps to reduce the risk of accidentally pouring the wrong solution into tower reservoir 318, or pouring the correct solution into the wrong tower reservoir. This helps to ensure that the correct chemistry is supplied to the correct location for each electroplating operation. The configuration of anolyte supply system 300 thus allows both semiautomated and fully automated filling of the anode chamber flow loop with water, acid, and tin, negating the need for human handling of chemicals.

[0079] FIG. 4 shows a flow diagram depicting an example method 400 for operating an electroplating apparatus. Method 400 may be executed by a controller, such as controller 325. Method 400 will be described with regard to anolyte supply system 300, but may be applied to other suitable systems.

[0080] Method 400 is described for an electroplating procedure that comprises a startup phase 402, an electroplating phase 404, and a maintenance phase 406. However, in some examples the phases may overlap, may include one or more intermediate phases, and/or may include one or more additional phases. FIGS. 5-9 schematically depict a simplified version of anolyte supply system 300. Flow of anolyte components is depicted by arrows. Open valves are depicted as white. Closed valves are depicted as black. Valves that are selectively opened and closed during a phase of operation are depicted in gray.

[0081] During startup phase 402, at 410, method 400 includes flushing an anode chamber flow loop with an acid pumped via an anolyte component supply system comprising at least a first valve manifold. The system, including the anode chamber flow loop, may be empty at the initiation of startup phase 402.

[0082] For example, at 500, FIG. 5 shows anolyte supply system 300 configured to flush anode chamber flow loop 305 with acid pumped from source of acid 337 via anolyte component supply system 330. In this configuration, acid flows through second valve manifold 382 via check valve 388 and fourth shutoff valve 386, while third shutoff valve 384 is closed, restricting the flow of tin solution. Similarly, first shutoff valve 342 is closed, restricting the flow of water into anolyte component supply system 330. Second shutoff valve 344 is open, allowing flow of acid through first valve manifold 340 though flow meter 346 and into anode supply valve manifold 350. Therein, high flow shutoff valve 352 is closed while low flow shutoff valve 354 is open, allowing a volume of acid to flow through flow restrictor 356, directional valve 358, and flow loop isolation valve 332. Acid may then pass through filter 310 into anode chamber flow loop 305. In some examples, acid may instead be flowed at a higher volume via high flow shutoff valve 352.

[0083] Returning to FIG. 4, at 420, method 400 includes supplying the anode chamber flow loop with a tin solution from a supply fluidly coupled to the first valve manifold. Any tin precipitates may be filtered (e.g., via filter 310) prior to entering the anode chamber flow loop. Tin may be supplied until the tower reservoir reaches a threshold fill level. For example, supplying the anode chamber flow loop with a tin solution may include ceasing to supply the anode chamber flow loop with the tin solution responsive to a signal received from a level sensor comprised in a tower reservoir of the anode chamber flow loop.

[0084] For example, at 600, FIG. 6 shows anolyte supply system 300 configured to fill anode chamber flow loop 305 with tin solution pumped from bulk chemistry supply 372 via anolyte component supply system 330. In this configuration, tin solution flows through second valve manifold 382 via third shutoff valve 384, while fourth shutoff valve 386 is closed, restricting the flow of acid. Similarly, first shutoff valve 342 is closed, restricting the flow of water into anolyte component supply system 330. Second shutoff valve 344 is open, allowing flow of tin solution through first valve manifold 340 though flow meter 346 and into anode supply valve manifold 350. Therein, low flow shutoff valve 354 is closed while high flow shutoff valve 352 is open, allowing a high volume of tin solution to flow through directional valve 358 and flow loop isolation valve 332. Tin solution may then pass through filter 308 into anode chamber flow loop 305.

[0085] Returning to FIG. 4, at 430, method 400 includes flushing the anolyte component supply system with the acid. This may help to prevent tin precipitating out of solution into a solid that can clog the lines and valves. For example, at 700, FIG. 7 shows anolyte supply system 300 configured to flush anolyte component supply system 330 with acid. In this configuration, acid flows through second valve manifold 382 via check valve 388 and fourth shutoff valve 386. Third shutoff valve 384 is closed, restricting the flow of tin solution. Similarly, first shutoff valve 342 is closed, restricting the flow of water into anolyte component supply system 330. Second shutoff valve 344 is open. This allows flow of acid through first valve manifold 340 though flow meter 346 and into anode supply valve manifold 350. High flow shutoff valve 352 is closed while low flow shutoff valve 354 is open, allowing a volume of acid to flow through flow restrictor 356 and directional valve 358, and into drain line 360. In some examples, directional valve 358 may allow flow of acid towards loop isolation valve 332. This flushes the supply line between directional valve 358 and loop isolation valve 332. In some examples, acid may instead be flowed at a higher volume via high flow shutoff valve 352.

[0086] Returning to FIG. 4, during electroplating phase 404, at 440, method 400 includes selectively dosing the anode chamber flow loop with the acid and water via the first valve manifold responsive to signals received from one or more sensors of the anode chamber flow loop. Further, at 450, method 400 includes restricting flow of the tin solution to the first valve manifold, for example by restricting opening of the third shutoff valve. In this way, tin solution filling does not occur during the electroplating phase. Third shutoff valve opening may be restricted by software-based commands from the controller, through physical restriction (e.g„ pneumatic force), by presenting warnings to the operator via a user interface, etc. The engagement of the acid source following tin solution filling may be a trigger for initiating this restriction. [0087] For example, at 800, FIG. 8 shows anolyte supply system 300 configured to dose anode chamber flow loop with either acid or water. In this configuration, third shutoff valve 384 is closed and restricted from opening. Fourth shutoff valve 386, which may be a normally open valve, is open. This allows for flow of acid through second valve manifold 382. At first valve manifold 340, first shutoff valve 342 is selectively opened, allowing for dosing of water into anolyte component supply system 330. Similarly, second shutoff valve 344 is selectively opened, allowing for dosing of acid into anolyte component supply system 330. Flow meter 346 may dose acid or water into anode supply valve manifold 350. In anode supply valve manifold 350, low flow shutoff valve 354 is open while high flow shutoff valve 352 is closed. This allows a controlled dosing of acid or water to flow through directional valve 358. To dose anode chamber flow loop 305 with either acid or water, loop isolation valve 332 is selectively opened. This keeps anode chamber flow loop 305 isolated unless dosing is indicated.

[0088] Returning to FIG. 4, maintenance phase 406 follows electroplating phase 404. As non-limiting examples, maintenance phase 406 may comprise changing an anode or a selective transport barrier in the anode chamber flow loop.

[0089] At 460, method 400 includes draining the anode chamber flow loop. For example, at 900, FIG. 9 shows anolyte supply system 300 in a configuration with loop isolation valve 332 open. This directs anolyte to drain line 360 via directional valve 358. First shutoff valve 342, second shutoff valve 344, and third shutoff valve 384 are all closed. This prevents new anolyte components from being introduced into anolyte component supply system 330 while anode chamber flow loop 305 is draining. After draining anode chamber flow loop 305, method 400 may include flushing anode chamber flow loop 305 with acid, as described with regard to FIG. 5.

[0090] Returning to FIG. 4, at 470, method 400 includes removing restrictions on opening the third shutoff valve. For example, the restrictions may be removed responsive to the completion or suspension of an electroplating process. Continuing at 480, method 400 includes flowing the tin solution to the first valve manifold by opening the third shutoff valve. For example, tin solution may be flowed to the first valve manifold as described with regard to FIG. 6. By filling the anode chamber flow loop in this way, the accuracy of the anolyte composition may be increased, allowing mixing of chemical in a safe, controlled manner and helping to avoid tin precipitation.

[0091] In some embodiments, the methods and processes described herein may be tied to a computing system of one or more computing devices. In particular, such methods and processes may be implemented as a computer-application program or service, an application-programming interface (API), a library, and/or other computerprogram product.

[0092] FIG. 10 schematically shows a non-limiting embodiment of a computing system 1000 that can enact one or more of the methods and processes described above. Computing system 1000 is shown in simplified form. Computing system 1000 may take the form of one or more personal computers, workstations, computers integrated with wafer processing tools, and/or network accessible server computers.

[0093] Computing system 1000 includes a logic machine 1010 and a storage machine 1020. Computing system 1000 may optionally include a display subsystem 1030, input subsystem 1040, communication subsystem 1050, and/or other components not shown in FIG. 10. Computing system 130, remote computing system 140, controller 225, and controller 325 are examples of computing system 1000.

[0094] Logic machine 1010 includes one or more physical devices configured to execute instructions. For example, logic machine 1010 may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0095] Logic machine 1010 may include one or more processors configured to execute software instructions. Additionally or alternatively, logic machine 1010 may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of logic machine 1010 may be singlecore or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and/or distributed processing. Individual components of logic machine 1010 optionally may be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. Aspects of logic machine 1010 may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

[0096] Storage machine 1020 includes one or more physical devices configured to hold instructions 1055 executable by the logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of storage machine 1020 may be transformed — e.g., to hold different data. [0097] Storage machine 1020 may include removable and/or built-in devices. Storage machine 1020 may include optical memory (e.g., CD, DVD, HD-DVD, Blu- Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage machine 1020 may include volatile, nonvolatile, dynamic, static, read/write, read-only, random-access, sequential-access, location-addressable, file-addressable, and/or content-addressable devices.

[0098] It will be appreciated that storage machine 1020 includes one or more physical devices. However, aspects of the instructions described herein alternatively may be propagated by a communication medium (e.g., an electromagnetic signal, an optical signal, etc.) that is not held by a physical device for a finite duration.

[0099] Aspects of logic machine 1010 and storage machine 1020 may be integrated together into one or more hardware-logic components. Such hardware-logic components may include field-programmable gate arrays (FPGAs), program- and application-specific integrated circuits (PASIC / ASICs), program- and applicationspecific standard products (PSSP / ASSPs), system-on-a-chip (SOC), and complex programmable logic devices (CPLDs), for example.

[00100] When included, display subsystem 1030 may be used to present a visual representation of data held by storage machine 1020. This visual representation may take the form of a graphical user interface (GUI). As the herein described methods and processes change the data held by the storage machine, and thus transform the state of the storage machine, the state of display subsystem 1030 may likewise be transformed to visually represent changes in the underlying data. Display subsystem 1030 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with logic machine 1010 and/or storage machine 1020 in a shared enclosure, or such display devices may be peripheral display devices. [00101] When included, input subsystem 1040 may comprise or interface with one or more user-input devices such as a keyboard, mouse, or touch screen. In some embodiments, the input subsystem may comprise or interface with selected natural user input (NUI) componentry. Such componentry may be integrated or peripheral, and the transduction and/or processing of input actions may be handled on- or off- board. Example NUI componentry may include a microphone for speech and/or voice recognition, and an infrared, color, stereoscopic, and/or depth camera for machine vision and/or gesture recognition. [00102] When included, communication subsystem 1050 may be configured to communicatively couple computing system 1000 with one or more other computing devices. Communication subsystem 1050 may include wired and/or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem may be configured for communication via a wireless telephone network, or a wired or wireless local- or wide-area network. In some embodiments, the communication subsystem may allow computing system 1000 to send and/or receive messages to and/or from other devices via a network such as the Internet.

[00103] It will be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.

[00104] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.